The long term goal of the Caltech Center for Excellence in Genomic Science (CEGS) is to develop and deploy the tools needed for the high-throughput creation of functional fusion proteins that tag endogenous gene products with a fluorescent protein, for the creation of marked mutant alleles of each protein, for the multiplex in situ hybridization of several different gene products in normal and perturbed embryos, for the analysis of the resulting patterns of expression with in toto imaging, and for the rendering/analysis of labeled cell positions and movements. Under the support of the parent grant, the development of each experimental tool has advanced to the point that they have been validated. This supplement requests support for the final steps in refining these technologies, through the support of four key senior post-doctoral fellows, including one involved in data management and establishment of a public interface. The supplement requests support for the supplies and small equipment needed to increase the rate at which data can be collected. The requested supplement will play a major role in advancing the goals of the Caltech CEGS grant into its production mode, enabling the advances made to date by key post-doctoral research to reach the scientific community in a much faster rate. Given the difficult job market today, these funds also will allow these talented young individuals the necessary time to secure appropriate positions at top-tier universities.